This invention relates to electrical connections to induction motors or the like which have two separate windings thereon, one of the windings being composed of a more coarse wire than the other winding. The specific embodiment of the invention described below is particularly adapted for a single phase induction motor but other uses for the invention may be apparent to those skilled in the electric motor manufacturing arts.
It is common practice, as shown in U.S. Pat. Nos. 3,793,611, 3,979,615 and in application Ser. No. 849,049 filed Nov. 7, 1977, to form electrical connections with coil wires by means of electrical terminals which have wire-receiving slots therein dimensioned to receive, and establish electrical contact with, the coil wire. Coil windings are usually insulated with a varnish-type film of insulating material such as polyvinyl formal resin and when the wire is moved relatively into the slot of the terminal, the edges of the slot penetrate the insulation of the wire and establish electrical contact with the conducting core of the wire. Terminals of this wire-in-slot type which are used to establish contact with electrical coils are usually provided with an additional contact means which can be connected to lead wires extending from the coil. This wire-in-slot terminating technique for electrical coils has been widely adopted for induction coils and for many types of electrical motors such as universal motors.
For several reasons, wire-in-slot type connections have not heretofore been used for induction motors. The windings of a typical single phase induction motor are comprised of a main winding which is usually of a relatively coarse gage wire and an auxiliary winding of a relatively finer gage wire. The circuitry normally requires that one end of each winding be connected to a common lead wire and the remaining ends be connected to separate lead wires. The disparity in diameters of the main and auxiliary windings presents termination problems which have discouraged the use of wire-in-slot terminations in the past. The use of this wire-in-slot technique has also been discouraged by reason of certain physical and dimensional limitations and requirements as explained in my co-pending application Ser. No. 887,584.
The instant invention is specifically directed to the achievement of improved terminating techniques for the windings of induction motors and particularly to the achievement of wire-in-slot terminations in an efficient and orderly manner for such motors. In accordance with the principles of the invention, three identical terminals are employed, each terminal having a first slot means which is dimensioned to receive the wire of the main winding and a second slot means which is dimensioned to receive the wire of the auxiliary winding. These terminals are used in conjunction with a terminal housing having three terminal-receiving cavities therein. Wire-admitting slots are provided in the housing which permit one end of the main winding to be located in the first cavity, one end of the auxiliary winding to be located in the second cavity, and the remaining ends of both windings located in the third cavity. When the terminals are inserted into the cavities, electrical connections are estabilished with the ends of the coil windings as required by the control circuit of the induction motor.
It is accordingly an object of the invention to provide an improved terminating means for the windings of an induction motor. A further object is to provide connecting means for establishing predetermined electrical connections between lead wires and coil wires of different diameters. A further object is to simplify and improve the manufacturing techniques for induction motor stators.